This document is a stand-alone version of the presentation I gave at the 33rd Colorado State Demography Office Annual Meeting. This includes much of the vocal portion recast as text and similar visuals.
Each year the State Demography Office in the Colorado Department of Local Affairs produces population estimates for all counties, municipalities, unincorporated areas, and Conservation Trust Fund Title 32 Special Districts. This amounts to about 522 geographies overall. For a more detailed dive into our methods click here.
Data Produced for Release:
Our county estimates are created by taking a base population (the Census 2010 population moved to July 1 by tracking components) and adding natural increase and net migration to come up with the next year’s estimate. This process is repeated for each year until the most current.
Each year these data are revised back to the base year as the estimate for the new year is created, this process is called Vintage, which is why we refer to each new set of estimates as a vintage. This year we are releasing Vintage 2014 estimates. The county estimates are the base for all other estimates, they are summed to generate the state estimates and are controls for sub-county estimates.
Our methodology changes for municipal, unincorporated areas, and special districts. We use the Housing Unit Method for these geographies because of frequent boundary change, the lack of reliable migration data for these areas, and stability of housing unit estimates over time. To put it more plainly, people move a lot and places annex a lot, but housing units tend to stay where they are. This methodology takes the housing unit counts in the Census and tracks change in those housing units through building permits and certificates of occupancy. Vacancy rates and persons per household data from the Census are used to estimates the population in the area. These estimates are broken down into parts based on which municipalities and counties the areas are in. At the end of the process, all of the estimates need to sum to the county totals and are adjusted to do so (through a process called raking). This process is repeated for each year, taking the prior year as a base
Similarly, these data are revised back to the base year each time a new year is added.
| Month | Process |
|---|---|
| November to December | Collect Housing Unit and Group Quarter Data |
| January to April | Receive and process input data and boundary changes. |
| May | Create draft county, municipality and district estimates and send to local governments for review |
| June to July | Receive and review population challenges and provide support to local governments. |
| August | Release population estimates. |
| September | Create tables and databases for website |
The United States has a population of 318,857,056 in 2014, growth of 2.3 million (0.7%) from 2013. Colorado grew by 82,485 (1.6%) to 5,353,471 in 2013. Colorado ranks as the second largest state in the Mountain Region (CO, MT, ID, WY, UT, NV, AZ, NM). Colorado ranks 4th in Nation for percentage growth in population behind North Dakota, Nevada, and Texas. Even more impressive, Colorado ranks 8th in the Nation for absolute population growth behind Texas, California,Florida, Georgia, Arizona, North Carolina, and Washington. This is especially remarkable because large states like Texas and California have large bases to grow from and can add large numbers of people with very slow growth. However, to put this in perspective, Harris County, TX (Houston) added more population than Colorado.
Despite incredible overall growth, population growth is not ubiquitous and population change varies greatly across the state. The map below shows changes in total population
The bulk of population growth since 2010 has been concentrated in the Front Range, specifically from El Paso County north through Denver to Larimer and Weld counties. Notably, there is significant population decline on the Eastern Plains and in some Western Slope counties. The concentration of growth is even more stark when considering Net Migration.